This invention relates in general to the construction of thrust engines and in particular to a new and useful thrust engine which includes a combustion chamber connected to a nozzle having a narrow neck portion of smaller diameter and a divergent portion which may advantageously include an extension which is provided with means for directing a control fluid therein for influencing the direction of the thrust vector.
The invention relates particularly to a jet engine with thrust vector control, where the thrust nozzle has an extension adjoining the nozzle end, which is widened beyond the expansion ratio corresponding to the ambient pressure, and wherein at least one selectively controllable control fluid feed point for the input of fluidic control pulses effecting a deflection of the thrust jet in the corresponding direction, is arranged in an end zone at the inlet end of the extension.
Jet engines of this type, work similar to fluidic elements by utilizing the Coanda effect with fluidic jet deflection by control pulses which are put-in, either temporarily, or, if the thrust jet does not adhere automatically on the thrust nozzle extension under the action of the Coanda effect, are applied for the duration of the jet deflection. It is known, with such engines, to arrange several selectively controllable parts acting in a main direction of deflection, distributed over the circumference of the nozzle in the range of the inlet end of the extension at a point where the narrow zone is formed which is particularly favorable for the deflection of the jet. At such locations the gas pressure in the thrust jet attains for the first time substantially the ambient pressure, or even drops below it, and an effective jet deflection can be obtained by weak control pulses. But this known fluidic jet deflection method has the disadvantage that the sensitive thrust jet zone does not remain stationary in the thrust nozzle or its extension in operation, but is displaced in the longitudinal direction of the nozzle in dependence on the combustion chamber pressure, on the ambient pressure, or on variations of the nozzle geometry, for example, as a result of melting of the inner boundary walls of the thrust nozzle. In this case the control fluid feed openings are no longer covered by this narrow thrust jet zone, and jet deflection is only possible with much stronger control pulses in terms of quantity and pressure, or the deflection stops completely, for example, when air with ambient pressure is sucked into the thrust nozzle zone by utilizing the vacuum in an input of control pulses, while the air intake openings, as a result of the displacement of the vacuum zone, are no longer under their influence.